psiroky commented on PR #166: URL: https://github.com/apache/maven-resolver/pull/166#issuecomment-1413808333
I _believe_ this change is the cause behind the "slowness" I am seeing when comparing Maven 3.9.0 and 3.8.7. See https://lists.apache.org/thread/r9p236z8kvqqk7ykvkgmc5wgps6n1hkf for some numbers comparing couple of different builds on 3.9.0 and 3.8.7. From what I was able to observe (using async-profiler and JFR/JMC) the number of created instances of `org.eclipse.aether.artifact.DefaultArtifact` is about 4 times higher with 3.9.0 (and the logic in the constructor is somewhat "complex", merging maps, which takes time and creates quite a lot "garbage"). For small projects this is not really noticeable (e.g. if you create 1k or 4k instances that is not something to noticeable slow down the build). However, for big multi-module projects (like e.g. Quarkus which I am using for testing), the difference is ~2mil objects vs ~8mil objects and that adds up. I have tried to revert this commit (on current maven-resolver master, since it is basically the same as version 1.9.4 which is used in 3.9.0) and then build the 3.9.x branch with that version (1.9.5-SNAPSHOT) -- and the result is that the build times are basically equal to those of 3.8.7. At this point I am not saying this change is bad or so, maybe we need to do adjustments elsewhere. Also, even ~2mil created `org.eclipse.aether.artifact.DefaultArtifact` seems like a lot, so maybe there is a space for some more aggressive caching (I am just speculating, since I have not studied the code in depth yet). Sorry for hijacking this old PR, but I wanted to let you know asap. I am planning to create a proper JIRA, but before that I need to gather a bit more data and double-check my findings. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@maven.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
